Clamping band



March 20, 1951 G. B. DESLOGE 2,545,653

CLAMPING BAND Filed Nov. 30, 1949 Patented Mar. 20, 1951 UNITED STATES PATENT OFFICE CLAMPING BAND George B. Desloge, University City, Mo., assignor to Watlow Electric Manufacturing Company, St. Louis, Mo., a corporation of Missouri 7 This invention relates to clamping bands and more particularly'to such bands for clamping split-ring type electrical heaters in place on a cylinder.

The object of the invention is the provision of a clamping band by means of which a split-ring electrical heater may be readily tightly clamped in' any "desired position around a cylinder to be heated by the heater, as, for example, the cylinder of a plastic molding press. Such heaters have terminals which extend radially outward on opposite sides of a split in the ring. The invention generally comprises a flexible clamping band which has means at the end of the band for drawing the band tight around the heater, and a jumper plate intermediate the ends of the band having an aperture therein for receiving the terminals of the heater without engagement of the terminals by the plate to avoid shorting the resistance heating wire of the heater. Other features will be in part apparent and in part pointed out hereinafter.

In the accompanying drawing, in which several of various possible embodiments of the invention are illustrated,

' Fig. 1 is a view in elevation illustrating a clamping band of this invention for clamping a onepiece split-ring electrical heater, the band being shown as applied to the heater;

Fig. 2 is a view in elevation illustrating an alternative iorm of clamping band of this invention for clamping a two-piece split-ring electrical heater, the band being shown as applied to the heater;

' Fig. 3 is a side elevation of either Fig. 1 or 2 as viewed on line 33 of Fig. l or Fig. 2;

Fig. 4-is a side elevation of Fig. 2 as viewed on line 4-4of Fig. 2; and,

5'is a section taken on and Fig.2.

5 Similar" reference characters indicate corresponding. parts throughout the several views of the drawing.

Referring to the drawing, there is shown at I in Fig. 1 a one-piece split-ring electrical heater for which a clamping band of this invention is speciallyadapted. This heater is formed by windingta coil of resistance heater wire 3 around a core 5 consisting of a fiat strip of electrical insulating material (Fig. 5). Thecoil is encased in a sheath 1 of insulating material. A metal strip 9 about as wide as the sheath 1 is placed against one side of the sheath and a wider metal strip II is placed against the other side of the sheath. The-side margins of the strip ll are line s 5 of Fig. 1

Application. November so, 1949, Serial No. 130,310

" v 9 Claims (Cl.219.-19)

bent over as indicated at 13 upon the side margins of the strip 5 to retain both strips in place. This leaves a groove [5 between the opposed side edges of the strip I l Terminal posts I! lead from the ends of the wire through the strip 9 at the ends of the assembly. These are insulated from the strip 9 and have nuts I 9 threaded thereon. The assemblyis bent into circular form with the terminal'posts I1 and consequently with the groove IE on the outside of the circle. The ends of the circularly bent assembly are separated at split 2| (Fig. l) the terminal post being on opposite sides of the split.

The clamping band for the above-described one-piece sp1itring heater 1 is generally designated 23 in Fig. 1. It comprises a generally rec tangular elongate jumper plate 25 of thin, flexible sheet metal, about as wide as the width of the heater and long enough to have an elongate longitudinal aperture or slot 21 therein which is longer than the arcuate distance between the terminal posts I i when the split-ring heater is expanded to some extent. Flexible sheet metal straps 29 are secured as by spot welding 31 to one face of the plate 25 (the face which is inside when the clamping band is placed around the heater) to extend in opposite directions from opposite ends of the plate in line with the slot 21. The ends of the straps terminate short of the slot 21 so as not to block the slot. The straps are narrower than the plate and also slightly narrower than the groove 15 so that they may fit in the groove (Fig. 5) Angle members 33 are secured as by welding to the free ends of the straps 29 upon the outer faces of the straps. These angle members are narrower than the straps and have opposed apertured outstanding arms 35 receiving a clamp bolt 31 upon which a nut 39 is threaded.

The plate 25 and the straps 29 are preferably made from a metalhaving a lower coefficient'of thermal expansion than the metal of strips 9 and H. They may be made, for example, of Invar, an alloy containing 63.8% iron, 36% nickel and 0.2% carbon, having a very low coeificient of thermal expansion. Also, as illustrated, one of the straps 29 is made short so that the length of the clamping band from the center of the jumper plate to the end of the short band is about of are around the heater, and the other strap is made long so that the length of the band from the center of the jumper plate to the end of the long strap is about 270 of are around the heater. Also, the straps preferably are made of material having a thickness approximately that of the metal strip H -of the."-heater-"and consequently through the slot 21 in the jumper plate 25 out of contact with the plate, the straps 29 being disposed in the groove l5 of the ring, with arms 35 of angle members 33 extending-radially outward. The bolt 31 is inserted through the apertures in the arms, nut 39 applied, and the bolt tightened to draw up the band tightly around the ring and clamp it tightly in any desired position on the cylinder. With the straps and jumper plate made of metal of a lower coefiicient of thermal expansion than the metal of strips 9 and l i of the heater, the band retains the heater clamped tightly on the cylinder when heated as well as when cool; With the straps 29 fitted in the groove I5, the jumper plate is prevented from shifting sidewise and contacting the terminal posts, thereby avoiding shorting of the heatin coil.

Fig. 2 illustrates a two-piece split-ring elec trical heater 4| and a clamping band 43 for this type'of heater. The two-piece heater is used on a cylinder which does not have an end over which the heater may be applied. The two-piece heater consists of two separate identical half rings 45, each of which is made like the ring I of Fig. 1 with the samecross-section as illustrated in Fig. 5; Each half ring 45 has a terminal post H extending radially outward at each of its ends. The half rings are placed on the cylinder with their ends opposed to oneanother and spaced apart as indicated at 41. s With the two-piece heater, there are two diametrically opposite sets of terminal posts to be jumped, as-will be clear from Fig. 2. Accordingly, the clamping band 43 is made with two jumper plates 25 each having a slot 21 to receive one of the two sets of terminals and with straps 29 joining the two plates and extending in opposite direoti'ons from the opposite ends of the two plates, the straps being spot welded to the inside faces of the plates as in the Fig. 1 form of the clamping band. Here the strap 25 joining the two jumper plates is made of such length that the length of the clamping band from the center of one plate to, the center of the other is about 180 of are around the heater. The two other straps 29 are provided at their ends with the angle brackets 33, the outstandingarms of which receive the clamp bolt 37 upon which the nut 39 is threaded. .;"-It"wil1--,be seen that in the Fig. 1 form of clampinghand, there is one long narrow strap 29 extending downward and then upward from the jumper plate-around the heater, while in the Fig. 2 form there is a first strap 29 extending downward and then upward around the heater from the jumper plate on the right to the jumper plate on the left, then a second strap 29 extending upward from the jumper plate on the left. In eflect,,,the length of the band from the jumper plate onthe right of Fig. 2 around to the angle member 33 on the ;left corresponds to the length of the band from the jumper plate in Fig. 1 around to the angle member 33 on the left.

In view of the above, it will be seen that the several objects ofthe invention are achieved and 911. 93 a van e s' sul sa ei 1 1.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A flexible clamping band for a split-ring type electrical heater which has terminals extending radially outward therefrom on opposite sides of a split in the ring, having means at the ends of the band for drawing the band tightly around the heater, and a jumper plate intermediate its ends having an aperture therein for receiving the terminals of the heater without engagement of the terminals by the plate.

-2. A flexible clamping band for a split-ring type electrical heater which has a flat-bottomed groove in its outer periphery and terminals extending radially outward from the bottom of the groove on opposite sidesoi a split in the ring, the band having a jumper plate wider than the groove intermediate .its ends, the plate having a longi-. tudinal slot therein for receiving the terminals without engagement of the terminals by the plate, the band also having straps narrower than the groove adapted to fit in the groove, and means at the ends of the band for drawing it tight around the heater. 3. A flexible clamping band for a split-ring type electrical heater which has a flat-bottomed groove in its outer periphery and terminals ex; tending radially outward from the bottom of the groove; on opposite sides of a split in the ring, the

band having a jumper plate wider than the,

groove intermediate its ends, the plate havinga longitudinal slot; therein for receiving the ter minals without engagement of the terminals by the plate, straps narrower than the groove: adapted to fit in the groove, and means at the. ends of the band for drawing it tight around the heater, the jumper plate being ofiset from the straps toward that side of the band which is outermost when the band is placed on the beaten,

4. A clamping band for a split-ring type electribal heater which has terminals extending radially outward therefrom on opposite sides of; a split in the ring, comprising a jumper plate having an aperture therein adapted to receive the terminals without engagement of the terminals by the plate, flexible straps extending in oppo site directions from the ends of the jumper late} and means at the ends of the band for drawing the band tight around the heater. i f -5. A clamping band tor a split-ring type elec trical heater which has terminals extending; radially outward therefrom on opposite sides-of a split in the ring, comprisinga juniper plateof; thin-riexiblesheet metal having an-elongatelongitudinal slot adapted to receive the {terminals without-engagement of the terminals by the plate, flexible straps of thin sheet metal narrower'than the plate extending in opposite directions from; the ends of the plate, and means at the ends'of the hand for drawing the band tight around the beaten a 6. A flexible clamping band comprising 0,- jumper plate of thin, fiexihlesheet metal having anelongate slot extending longitudinally .of-the flexible straps of thin, flexible sheet metal narrower than the plate spotwelded toone face of the plate at its opposite ends and extending opposite directions from the ends of the plate in. line with 'theslot in the plate, and angle nem ha a theme at theme -he i ma! tending outward on the same side of the straps as the jumper plate, said arms being apertured to receive a clamp bolt.

7. A flexible clamping band comprising two elongate jumper plates of thin, flexible sheet metal, each plate having an elongate slot extending longitudinally of the band, said plates being joined by an intermediate flexible strap of thin, flexible sheet metal which is narrower than the plates and spot welded at each of its ends to one of the faces of a respective plate, each weld being at one end of the plate and in line with the slot in the plate, and flexible end straps of thin, flexible sheet metal of the same width as the intermediate strap, each end strap being spot welded at one end to the same face of a respective one of the plates, and angle members at the ends of the end straps on the same side thereof as the plates, said angle members having outstanding arms which are apertured to receive a clamp bolt.

8. A flexible clamping band for a split-ring type of electrical heater which has at least one terminal extending radially outward therefrom, means at the ends of the band for drawing the band tight around the heater, and a jumper portion intermediate its ends having an aperture therein for receiving the terminal of the heater without engagement of the terminal by the jumper portion.

9. A flexible clamping band for a circular splitring type electrical heater which has at least one flat-bottomed groove between raised portions on its outer periphery and at least one terminal extending radially outward from the bottom of the groove, the band having a jumper plate wider than the groove and adapted to rest on said raised portions, the plate having an opening therein for receiving the terminal without engagement of the terminal by the plate, said band having straps narrower than the groove adapted to fit therein and attached at the ends to the jumper plate, and means at the other ends of the band for drawing it tight around the heater.

GEORGE B. DESLOGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,244,817 Willson Oct. 30, 1917 FOREIGN PATENTS Number Country Date 364,452 Germany Nov. 24, 1922 392,014 Germany Mar. 21, 1924 394,943 Germany May 7, 1924 

